I have read 20l is biggest bath the Bluetooth wifi model will do. I use mine for cheese making. Can i control a 20l bath with additional 20l milk bain marie style or can I only 20l sum of all parts. I have been doing 6l batches milk, works really well, but want to tipple output for some cheeses. Help appreciated.

I think you could warm a lot more liquid if you use a well isolated container. I my self have a setup with a pizza delivery box that I made waterproof. I don’t use milk in it but the water stays at temperature for hours after the ANOVA is removed. In a normal container heat is lost at a much higher rate. Because the box is so well isolated I can use more water than I could use with a non isolated polycarbonate container.
Making the pizza delivery box was a lot of work. You could also use a cool box. Conversion of these for sous vide instructions can be found on YouTube. I don’t know if this system would work for two times the liquid as normal though.
In general I think polycarbonate boxes are not very energy sufficient.

BEWARE!!! This Kangabox will leak! See the thread for more info…
This is my setup. It’s a Kangabox 32 liter container.
The box is called thermobox easy.
Material is EPP. It’s a lot tougher than styrofoam.
Made a hole in the top of 60 mm and the Anova is a nice tight fix.
This box is very well isolated and therefore the right fit for a long look.
On the inside I have made marks for the maximum water level. The Anova sticks in over 3 cm beyond the minimum mark.
That’s a bit of a concern but…

@Goshin has the right idea in my opinion. Using an insulated container will allow you heat and maintain temperature of much more water in your bath. I use a Colman cooler with an insulated cover when I do longer, larger cooks. The important thing is that it insulates against heat loss so your Anova doesn’t have to work extra hard to maintain temperature.

i’ve whacked my gen 2 wifi anova in approx 50L of water and it kept it at 68.5 for a few days without issue. however, i have not tried to keep it at higher temps. unsure what temp you need for your activities.